Introduction

Dry running bearings are widely used in applications where external lubrication is not feasible. These bearings rely on solid lubrication mechanisms and material design rather than oil or grease.

However, compared with lubricated systems, dry running bearings are more sensitive to load, speed, surface condition, and material limits, which often leads to premature failure if not properly selected or applied.

For both engineers and procurement teams, understanding why dry running bearings fail—and how to fix these issues is essential for ensuring reliability and reducing long-term costs.

Dry Running Bearings Failure Mechanism: What Happens in Real Operation

Dry running bearings operate under boundary or solid lubrication conditions, where a thin transfer film or low-friction layer separates the shaft and bearing surface.

· Solid lubricant transfers to the shaft

· A thin film reduces direct contact

· Friction is controlled by material properties

Failure begins when this film becomes unstable or breaks down.

Why Dry Running Bearings Fail: Key Causes

1. Transfer Film Breakdown

· Poor film formation

· Film removed under high load or speed

· Surface mismatch

Once the film fails, direct contact leads to rapid wear.

2. Excessive Load or PV Limit Exceeded

Dry bearings are highly sensitive to PV value (Pressure × Velocity):

· High load → increased contact stress

· High speed → increased heat

If limits are exceeded:

· wear accelerates

· material degrades quickly

3. Overheating and Poor Heat Dissipation

Without lubrication, heat cannot be effectively removed.

· temperature rises rapidly

· polymer layers soften

· structural deformation occurs

4. Shaft Surface and Installation Issues

Surface roughness and alignment directly affect performance:

· rough surface → abrasive wear

· misalignment → localized stress

· contamination → rapid damage

Research shows that surface condition significantly affects friction and wear behavior in bearing systems.

How to Fix Dry Running Bearing Failures

Instead of simply replacing failed parts, effective solutions focus on correcting root causes:

1. Optimize Material Selection

Choose materials designed for dry-running conditions, such as:

· Metal-Polymer Composite Bearings

· Bi-Metallic Composite Bearings

These structures combine low-friction layers with strong backing materials, improving wear resistance and load capacity.

2. Control Load and PV Conditions

· verify actual operating load

· reduce peak stress

· ensure working conditions stay within limits

3. Improve Heat Dissipation

· use metal-backed structures

· optimize housing design

· avoid continuous overload operation

4. Improve Shaft Surface Quality

· optimize roughness

· ensure proper hardness

· maintain alignment

5. Use Application-Specific Bearing Types

Different structures are suitable for different conditions:

· Bronze Wrapped Bearings → suitable for wear resistance

· Filament Wound Composite Bearings → high load & impact resistance

Selecting the right type is often more effective than simply upgrading material.

Procurement Checklist: How to Avoid Failure Before It Happens

To reduce risk at the sourcing stage, procurement teams should focus on:

· PV rating vs real operating condition 

· material system (not just product name) 

· sliding layer thickness and consistency 

· application validation data 

· supplier experience in dry-running environments 

Because dry-running performance depends heavily on material and manufacturing consistency, supplier capability is often more critical than price.

Conclusion

Dry running bearing failures are typically not caused by a single factor, but by a mismatch between material capability and operating conditions.

By understanding failure mechanisms and applying proper selection, design, and sourcing strategies, both engineers and procurement teams can significantly improve performance and reduce lifecycle costs.

Further evaluation and testing under real working conditions remain essential for achieving reliable dry-running performance.